Fixed displacement motor or pump



2 Sheets-Sheet 1 l|||l l Q Q v 1957 v E. ORSHANSKY, JR

FIXED DISPLACEMENT MOTOR OR PUMP Filed Sept. 24, 1965 m mm ML L H v r A3 United States PatentO 3,348,495 FIXED DISPLACEMENT MOTOR R PUMP EliasOrshansky, Jr., 1079 Lombard St., San Francisco, Calif. 94109Filed'Sept. 24, 1965, Ser. No. 489,823 3 Claims. (Cl. 103-173) ABSTRACTOF THE DISCLOSURE A fixed displacement hydraulic motor or pump havingdouble wobble plates at each end of a fixed cylinder block, said doublewobble plates having an outer cam surface and an inner cam surfacewherein the inner cam surface makes a greater angle to normal than theouter cam surface the block having an inner tier of piston-valvesmounted therein bearing against the inner cam surfaces and an outer tierof piston-valves mounted in said block bearing against the outer camsurfaces, each of said piston-valves serving as a piston acting on onecam surface and as a valve acting on an opposed cam surface.

This invention relates to a hydraulic motor or pump, and moreparticularly relates to a fixed displacement hydraulic motor ofsimplified construction. a

An object of the present invention is to provide a fixed displacementhydraulic motor or pump which is capable of transmitting a large amountof power for its size.

Another object of the invention is to provide a fixed displacement motoror pump of simplified construction having relatively few moving parts.

Still another object of this invention is to provide a fixeddisplacement motor or pump which is provided with anti-frictionbearings.

A further object of this invention is to provide a motor or pump whereineach driving piston also acts as a valve for a piston on the other tier,and wherein the valves of one tier have three lands, While those ofanother tier have two lands.

A still further object of the invention is to have separate drive andretraction cams for each tier.

Other objects will become apparent from the balance of thisspecification as follows.

In the drawings forming part of this application:

FIGURE 1 is a side view in section of a motor or pump embodying thepresent invention, said view being on the lines 1--1 of FIGURES 2 and 3.

FIGURE 2 is a sectional view of the line 2-2 of FIG- URE 1.

FIGURE 3 is a sectional view on the line 3--3 of FIG- URE 1.

Referring now to the drawings by reference characters, there is shown amotor or pump having a fixed housing, generally designated 5, having ashaft 7 mounted for rotation therein on end bearings 9 and 11. Mountedon the shaft 7 for rotation therewith are two Wobble plate assemblies 13and 15. The wobble plate assemblies are mirror images of each other soonly one will be described in detail. Wobble plate assemblies have anouter plate 17 and an inner plate 19, the plates comprising an outerrace 21 and an inner race 23, with needle bearings 25 separating the tworaces. For the purposes of illustrating the invention, the outer wobbleplate assembly 13 and the inner wobble plate assembly 15 are shown asbeing 180 out 3,348,495 Patented Oct. 24, 1967 of phase in theembodiment illustrated, so that the power strokes will be 90 out ofphase. It will be noted from the drawings that the outerplate 17 makesan angle of approximately 12 from a plane normal to the shaft, while theinner plate 19 makes an angle of about 15 to said plane. This is toequalize the length'of piston travel in the inner and outer tiers ofpistons. I s

Mounted within the housing 5 and aflixed thereto is the cylinder block27, which has a first central passage 29 around its periphery and twoouter passages 31 and 33. It will be understood that the outer passages31 and 33 will be connected together and may serve as the high pressureline, while the center passage 29 is the low pressure line, or viceversa. The cylinder block is provided with an outer row of cylinders 35and an inner row of cylinders 37. The outer row of cylinders constitutesa relatively large outer cylinder 39 opening against the Wobble plateassembly 15 and a relatively small cylinder 41 opening against thewobble plate assembly 13. The inner row of cylinders 37 are just theopposite, so that a large opening 43 faces the wobble plate assembly 13,while a relatively small cylinder 45 faces the wobble plate assembly 15.

As has been said before, the pistons of the outer tier have three lands,while the inner tier pistons have two lands. Each of the pistons, boththe outer and inner pistons, have a relatively large power portion 43and a relatively small retracting rod 45. The retracting rod telescopesinto the large portion of the piston as illustrated and is biasedoutwardly by the spring 47.

Each of the outer tier of pistons has a center land 51, an outer land53, and an inner land 54. As can best be seen from FIGURE 3, the valvingportion of the piston, comprising the three lands described, is in fluidcommu-'-. nication with the outer passage 31 and the passage 29. Apassage 56 leads from the valve portions of the outer row of pistons tothe power portion of the inner row of pistons.

The inner row of pistons also has an enlarged end 43 and a reducedretracting rod 57. These pistons have a first land 59 and a second land61 with the open portion in fluid communication with the passages 29 and33. Passages 55 lead from the valving portion of the inner tier ofpistons to the power portion of the outer tier of pistons,

so that the inner pistons serve as valves for the outer pi tons and viceversa.

I claim:

1. A fixed displacement hydraulic motor or pump comprising incombination:

(a) a fixed cylinder block,

(b) a shaft passing through said block and mounted for rotation relativethereto,

(c) first and second double wobble plates affixed to said shaft, one ofsaid plates being located at each end of said block,

(d) each of said double wobble plates having two concentric camsurfaces, namely an inner cam surface and an outer cam surface,

(e) the said inner cam surface making a greater angle to normal from theshaft than the outer cam surface thereby equalizing piston travelagainst the two cam surfaces,

(f) an outer tier of pistons mounted for reciprocation in said block,each of said pistons having a head bearing against the outer cam surfaceof the first wobble plate, and a retractor of reduced diameter V j I it.3,348,495

bearin g ag ainst the outer cam surface of the second wobble plate,

(g) an inner tier of pistons mounted for reciprocation in said block,each of said pistons having a head bearing against the inner cam surfaceof the second wobble plate and a retractor of reduced diameter bearingagainst the inner cam surface of the first wobble plate, and

(h) each of the pistons having a spool valve formed asa part thereof,wherein each of the inner tier pistons serves as a valve for a matingpiston on the outer tier and vice versa.

2. The structure of claim 1 wherein the retractors telescope into thepistons and are biased outwardly by a spring.

3. The structure of claim 1 wherein each of the pistons on one tierincludes a three land spool valve and each of 4 the pistons on the othertier includes a two land spool valve.

References Cited UNITED STATES PATENTS 2,010,378 8/1935 Sassen 1031742,437,887 3/1948 Mott 103-162 2,504,041 4/ 1950 Orshansky 1032272,545,929 3/1951 Orshansky 103-38 3,050,005 8/1962 Pschunder 103-38FOREIGN PATENTS 791,604 3/ 1958 Great Britain.

DONLEY I. STOCKING, Primary Examiner.

W. L. FREEH, Assistant Examiner.

1. A FIXED DISPLACEMENT HYDRAULIC MOTOR OR PUMP COMPRISING INCOMBINATION: (A) A FIXED CYLINDER BLOCK, (B) A SHAFT PASSING THROUGHSAID BLOCK AND MOUNTED FOR ROTATION RELATIVE THERETO, (C) FIRST ANDSECOND DOUBLE WOBBLE PLATES AFFIXED TO SAID SHAFT, ONE OF SAID PLATEBEING LOCATED AT EACH END OF SAID BLOCK, (D) EACH OF SAID DOUBLE WOBBLEPLATES HAVING TWO CONCENTRIC CAM SURFACES, NAMELY AN INNER CAM SURFACEAND AN OUTER SURFACE, (E) THE SAID INNER CAM SURFACE MAKING A GREATERANGLE TO NORMAL FROM THE SHAFT THAN THE OUTER CAM SURFACE THEREBYEQUALIZING PISTON TRAVEL AGAINST THE TWO CAM SURFACES, (F) AN OUTER TIEROF PISTONS MOUNTED FOR RECIPROCATION IN SAID BLOCK, EACH OF SAID PISTONSHAVING A HEAD BEARING AGAINST THE OUTER CAM SURFACE OF THE FIRST